Process for the recovery of alcohol and ether from admixture with air



E. BINDSCHEDLER.

PROCESS FOR THE RECOVERY OF ALCOHOL AND ETHER FROM ADMIXTURE WITH AIR.

APPLICATION FILED AUG.2, I920.

Patented Apr. 26, 1 9210 r wu. Nd E: Vh d m M L; ATTORNEY.

unirso STATES PATENT OFFICE.

EMILE BINDSCHEDLER, OF ZPHILADELPHIA, PENNSYLVANIA.

PROCESS FOR THE RECOVERY OF ALCOHOL AND ETHER FROM ADMIXTUBE WITH AIR.

Specification of Letters Patent. ptg bed A 2% 1921 Application filed August 2, 1920. Serial No. 400,586.

To (171 whom it may concern:

Bc it known that I. EMILE BINnsoHnnLER, a citizen of the Republic of Switzerland, residing in the city and county of Philadelphia, in the State of Pennsylvania. have inventcd a certain new and useful Improvement in Processes for the Recovery of Alcohol and Ether from Admixture with Air, of which the following is a true and exact description, reference being had to the accompanying drawings, which form a part thereof.

The object of my invention is an economical and efficient recovery of alcohol and other used as solvents in the manufacture of smokeless powder, artificial silk and other filaments from nitrocellulose or any other processes where similar solvents are used.

In the manufacture of artificial silk, for instance, a mixture of alcohol and ether is generally used for dissolving the nitrocellulosc. After the spinning of the col-lodium so obtained, said solvents are mixed with a large volume of air from which they have to be recovered. For this purpose concentratcd sulfuric acid has been used. Sulfuric acid has provedto be a suitable absorbent for alcohol and ether even when expanded. at very low percentage in air because it gives a chcn'lical reaction with both solvents according to the following equations:

In the first case alcohol with sulfuric acid gives ethylsulfuric acid and water, in the second case a complex additional compound (as per above formula) is probably formed between ether and sulfuric acid. Upon hcating in the presence of water, both compounds according to formulas 1 and 2, are decomposed producing alcohol and ether respectively and the sulfuric acid is regenerated for further use. The result of these decompositions may be expressed as'follows:

By simultaneous reaction of both alcohol and ether upon H 530 the products formed are therefore ethylsulfuric acid, the compound CQH SO and water. The latter decreases the strength of the concentrated H 550 and therefore cuts down its absorption capacity for ether.

This has already beendemonstrated by Barthlmy (Matieres grasses 7 42.08, Joum. Soc. Chem. Ind. 33, 915), who states that the absorption ca )acity of H 50, for ether is a function 0 its specific gravity and that an acid containing one molecule or more will absorb little ether or none and furthermore that an equimolecular mixture of ether and strong H SO is deprived of its ether by the passage of moist air after, sufficient hydration of the acid.

Based on these facts and in order to obtain-a high yield of recovery it becomes essential to make a distinct separation in the absorption process of said alcohol and ether mixture in such a way that the alcohol be absorbed first and the ether only after the alcohol has been removed as completely as possible.

It is the object of my invention to avoid the dilution of the concentrated H SQ, by water formed by its combination with alcohol with its consequent loss of absorptive capacity for ether, and my process consists broadly in first bringing the air mixed with alcohol and ether into intimate contact with water which will absorb the alcohol almost completely together with some of the ether. After this treatment I bring the air and ether into intimate contact iWlth concentrated H 80 to absorb the remaining part of the ether. Subsequently I recover the alcohol and ether in well known ways.

For the best results it is highly desirable that the water used for absorbing the alcohol should be maintained at a very low temperature. A temperature at or below the freezing point is desirable and freezing will be prevented by the admixture of alcohol with the water or by dissolving in the water salts which will lower its freezing point without interfering with its absorptive capacity for alcohol.

The detail of my process and of the apparatus I have devised for its practice will. be best understood as described in connection with the drawing which is a diagrammatic showing of an apparatus or plant devised for use with my process and in which A is a fan drawing the air mixed with alcohol and ether from the chamber where it is formed and for'cin it through acoolin device B and conduit into the bottom 0 an absorption towerC filled with some suit able material for insuring contact between the rising gas and vapor and a descending body of water or Weak alcohol solution sprayed into the top of the tower at M From the top of tower C the air and ether partly freed from alcohol pass through conthe absorption tower F into the to of which gpncentrated H SO is sprayed from head passes from tower F through conduit F to and through cooler B, where it absorbs heat from the air and vapor forced in by fan A, and thence through conduit G which may, after purification, lead to the spinning machines an%, after fresh admmture' with alcohol an ether, thesame air can return through fan A. This reuse of the air is to save any ether not absorbed in tower F,

H is a water inlet pipeithrough which water cooled down, preferably to or below zero, by passing through a cooler on refrigerator G passes to pipe H and spray head H After passing through tower D the weak alcohol solution passes through conduit I to a distributin pipe I which opens into the two tanks fend K. Valves located at J and J control the fiow into tanks K and K both from pipe I and distributin" pipe C to be described, and similar Y va ves located at L and I2 in outlet pipes K and K control the flow from tanks K and K and the operation of these valves is made automatic by the rising and falling of floats J and J and connected mechanism of a familiar type which, as it forms no part of my invention, T have only indicated diagrammatically.

From one of the tanks K or K and through pipes K and M the weak alcohol solution is drawn by pump M and forced into tower 0 through head M and after passing through the tower the solution passes through pipe C refrigerator G and pipe C to the distributing pipe- C. The alcohol solution is drawn off from tanks K and K through pipe K and pipe N to. a

fractionatin distilling column 0 heated by a steam c011 O and the vapors passing through conduit 0 enter first the alcohol condenser P from which the ether passes through conduit P to the ether condenser P The alcohol from condenser P flows through pipe Q and alcohol tail box Q to tank Q and the ether from condenser P fiows through pipe R andtail box R to tank R.

tanks S or S passes t rough pipe V to the The air freed from recoverable ether current to the rising alr and vapors passes The concentrated H SO holdin the ether in combination flows from tower T through pipe T to distributing pipe T opening into the tops of tanks S and S which are govided with pipes similar to tanks K and a distributing ipe Z opening into both tanks at top and two outlet ipes S and S opening into the bottoms of the tanks and these four ipes are provided with reversing valves and float actuators as before described. From pipe S the acid with more or less ether absorbed in it is drawn-off from the full tank S or S through pipe U and by ump U forced through cooler U into head i in tank F. F romipe S the acid from and supplied with the necessary water from reservoir Y and the ether vapor asses through conduit W to condenser and after condensation through pipe X and tail box X to tanlnRt The acid in still W, after losing absorbed ether, is drawn oil' through pipe W to a concentratingplant indicated at Z and the concentrated acid after being cooled, in refrigerator Z preferably to about zero, passes through pipe Z pump Z and I ipe Z to distributing pipe Z and to tank or S.

In. operation the air mixed with alcohol and ether is pumped out of its place of origin by the fan A and passing first through the cooler B passes successively to a series of two or more towers, two only being shown, the air entering the bottom of the tower C and passing up through the filling of the tower and then passing into the tower D and through the filling in that tower. The very cold pure water is introduced into the tower D and passing down in a counteras aweak solution of alcohol into one of the tanks K or K and from these tanks it is pumped by the pump indicated at M into the top of the tower C through the filling of which it passes down and leaving the tower passes through a cooler G and back into the tanks K, K. An amount of the alcohol solution formed by this treatment equivalent to the water supply forced into the tank D is drawn off through the conduit N into the still 0 and the alcohol and ether separated in the condensers P and P and stored .in the tanks Q and R The air and ether leaving the tower D-and free from alcohol pass through the refrigerator indicated atE, the main function of which is to so cool the air and gases as to precipitate any moisture and thus deliver the air and ether into the bottom of the absorption tank F free from water which would tend to dilute the concentrated sulfuric acid fed into this tower at its top. The ether is absorbed in the acid in the tower F and the airwhich may contain some residual ether passes through the c0nduitF'- to the heat exchange device indicated at B Where it cools the entering mixture of air and vapors, passing thence through the-pipe Gr it may, upon purification, return to the chamber, not shown, where the mixture of air and alcohol and ether originates, for. instance the spinning machine of an artificial silk plant.

The concentrated sulfuric acld is contained in tanks S and S into which the acid from the tower F is delivered through the pipes T and T and from which thesupplJy for the tower is drawnby the pump through the conduit U and preferably through a cooler indicated at U. When the acid has taken up sufficient ether it is drawn from the 'tanks through the pipe V to a still W where it is mixed with about half its volume of water and heated so as to drive off the ether which is condensed in the condenser X and asses through the pipe X and tail box 2 to the ether tank R the dilute acid from the still ,W is drawn ofi' from its bottom through the pipe W concentrated in a usual concentrating plant indicated at Z, refrigerated at Z and passes from the refrigerator through the pipe Z, pump Z and pipe Z to the distributing pipe Z and the tanks S, S.

. Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

l. Themethod of recovering alcoholand ether from a mixture of their vapors with air, consisting of first bringing the mixture into intimate contact with water'to bring about the absorption of the alcohol, subsequently bringing the air and ether mixture freed from alcohol into intimate contact with concentrated sulfuric acid to bring L about the absorption of the ether and sepawith concentrated sulfuric acid to bring about the absorption of the ether maintaining a low temperature of the liquid absorbcuts during the treatment for absorption concentrated sulfuric acid to bring about the absorption of the ether, maintaining a circulation of the acid in the absorption chamber until it has absorbed a sufiicient amount of ether.

4. The method of recovering alcohol and ether from a mixture of their vapors with air, consisting of first bringing the mixture into intimate contact with a solution of alcohol and water and then with pure water to bring about the absorption of the alcohol', subse uently bringing the air and ether mixture, reed from alcohol, into intimate contact with concentrated sulfuric acid to bring about the absorption of the ether and separating the alcohol and ether from said absorbents.

5. The method of recovering alcohol and ether from a mixture of their vapors with air, consisting of first bringing the mixture into intimate contact with water having dissolved in it a substance which will lower its freezing point to bring about the absorption of the.alcohol, subsequently bringing the air and ether mixture, freed from alcohol, into intimate contact with concentrated sulfuric acid, to brin about the absorption of the ether, maintaining a low temperature of the liquid absorbents during the treatment for absorption and separating the alcohol and ether from said absorbents.

the absorbents.

EMILE BINDSCI-IEDLER. 

